Police investigating a serious gang-related stabbing in Christchurch say they are dealing with a "tricky group of people" but making good progress.

A 33-year-old man was dumped outside Christchurch Hospital about 8.30pm on Saturday with significant lacerations to his head.

He remains in a critical but stable condition.

Detective Senior Sergeant Darryl Sweeney said police knew who was driving the car, which dropped the man at the hospital.

The incident is believed to be gang related.

"It's going to take some time to resolve this. They're a tricky group of people deal with, but we're satisfied we're making good progress."

Speaking to the victim would be "pretty helpful" but that was not possible yet, he said.

Detective Sergeant Hamish Wilson yesterday said a scene examination was being conducted at a semi rural address on the outskirts of Christchurch.

"This was a very personal and callous attack, and the victim's injuries are significant. Detectives were working throughout the weekend and continue to work around the clock in an effort to identify and locate the person or people responsible," he said.

"We are following positive lines of inquiry but we would like anyone who has any information to come forward and speak to the police."

Anyone with information is asked to contact Christchurch police on (03) 363 7400.